Quaking AspenQuaking Aspen

Insect Defoliation & Aspen Canker

Erin Redding Photo: Unknown 

Ecological ImportanceEcological Importance

Photo by M. & J. StoufferPhoto by Dwight Phillipswww.bentler.use

Photo: Clipart.comwww.fortliard.com/climate

Economical ImportanceEconomical Importance

• CratesCrates• Pallets• Matchsticks• Matchsticks• Tongue depressors• Ice cream spoons• Ice cream spoons• Furniture• House trim• House trim• Animal beddingS• Saunas

Fergus, 2005

Photo by Tim Morris

Quaking AspenPopulus Tremuloides

Most widely

distributed tree distributed tree

in North

America.

Can survive temperatures between -

57°C and 41°C (Perala and Carpenter,

Little (1

971)

1985).

Quaking AspenPopulus Tremuloides

• Pi i• Pioneer species

• Fast growing

• Shade intolerant

• Short life spanp

• Found on disturbed sites

• S d ll il• Sandy or gravelly soils

USDA Plant Profile

FloweringFlowering

• Flowers bloom in mid-spring

Image from DeByle, Norbert V and Robert P. Winokue, ed. 1985. Aspen: Ecology and management in the western United States. USDA Forest Service Gerenal Technical Report RM‐119, 283p.Flowers bloom in mid spring

before leaf-out

• Trees are usuall dioecious • Trees are usually dioecious

• Flowers are wind pollinated

Seedling EstablishmentSeedling Establishment

• Seeds are wind dispersed Seeds are wind dispersed

• Germination can occur between

2°C and 30°C ( h )2°C and 30°C (McDonough, 1979)

• Germination does not depend on

l h

Photo byTree NM

light (Faust, 1936 as cited by Barnes 1966)

• Rootlets cannot break through leaf

Female Catkin

litter. Seeds will only survive if

they fall on bare soil (Fergus, 2005).

Photo by B. Campbell

Root SproutsRoot Sprouts

• More common and more successful than

reproduction by seed

• New shoots grow from parent root systems

• Vegetative reproduction creates large

clones

• Clones can live for thousands of years

• I di id l i l ll

PANDO

Fishlake National Forest, Utah

• Individual trees in a clone are equally

genetically predisposed to biotic stressors (Barnes 1966; Fergus 2005)(Barnes, 1966; Fergus, 2005)

CompetitorsCompetitors

• Without frequent disturbance, aspen are replaced by trees with Without frequent disturbance, aspen are replaced by trees with

longer lifespan and/or more shade tolerance.

• Forest fire keep aspen from being outcompeted• Forest fire keep aspen from being outcompeted

Insect DefoliationInsect Defoliation

Photo by S Katovich

Forest Tent CaterpillarMalacosoma disstria

• LepidopteraLepidoptera

• Native to North America

l b• Generalist Herbivore

– Quaking aspen, Oaks (Quercusspp.), Gums (Nyssa spp. and

Liquidambar styraciflua) (Meeker, 2008)

b d fl d f l• Eat buds, flowers, and foliage

Photo by G. McIlveen, Jr.

Life CycleLife Cycleof Forest Tent Caterpillarp

Egg masses100 to 350 eggs

Form band up to 2 5cm long

Photo by Jeffrey Lotz

Form band up to 2.5cm longOverwintering stage

Hatch mid-February to April

5 instars Photo by Jeffrey Lotz

Mature LarvaeD k b h bl k

5 instars

Photo by James R Meeker

Dark gray to brownish blackSparse white hairs

Pale blue lines5 to 6 4 cm Photo by J D HarperPhoto by James R. Meeker5 to 6.4 cm Photo by J.D. Harper

Spin cocoons of silk in folded leaves

Transformation takes 10 days

Adult mothTan to brown

Dark lines through forewings2 5 to 4 5 cm

Transformation takes 10 days

Photo by Jeffrey Lotz

2.5 to 4.5 cmLate Spring

Live 1 day to 2 weeks

Meeker, 2008; Batzer and Morris, 1978

Impact on the TreeImpact on the Tree

• Re-flush smaller, fewer leavesRe flush smaller, fewer leaves

• Branch dieback

h• Crown thinning

• Less carbohydrate storage

• Loss of vigor

• More susceptible to 2° stress More susceptible to 2 stress

agents

• Death Photo by godurango.com• DeathGregory and Wargo, 1986 as cited by Fitzgerald, 1995,

226

Predisposing Factorsp g

• FTC is a native insectFTC is a native insect

– Many native parisitoids

• P t i t t b t • Pest can survive temperatures between -

40°C and 38°C (Batzer and Morris, 1978).Photo by J.D. Harper

• Forest fragmentation and edge effects

– Faster development of outbreaks

– Outbreaks last longer

(Roland, 1993)

Inciting Factorsg

• Outbreaks lasting several yearsOutbreaks lasting several years

– Tree loses too much vigor to respond to environment as adapted

Contributing Factorsg

• DroughtDrought

• Insect borers

• Fungi

– Hypoxylon (canker)

– Nectria (canker)

– Fomes (stem decay)

Control Optionsp

• Preemptivep

– Maintain vigorous growth

– Do not grow aspen in fragmented stands

– Minimize other stresses

• Reactive

– Do nothing

– Physical Removal

d– Pesticides

• Bacillus thuringiensis– Biological Controlg

• Entomophaga

Aspen CankerAspen Canker

Photo by na.fs.fed.us

Hypoxylon mammatumHypoxylon mammatum

• AscomycotaAscomycota

• Found throughout the

range quaking aspen

• C k f• Canker rot fungus

Photo by William Jacobi

Life CycleLife Cycleof Hypoxylon mammatumyp y

(Probably…)

Wind or water borne ascospores enter tree Infect living tissue underneath

bark

Wind or water borne ascospores enter tree

through wounds

mon

ths o

f

ectio

n

5-14

m infe

Ascospore (sexual spores) are produced in

perithecia

B t bl k d ll

C idi d d

Brown to black and very small

Conidia (asexual spores) are produced

Gray and powdery

Photos from Anderson and Anderson, 1979

Impact on the TreeImpact on the Tree

• Yellow sunken areasYellow sunken areas

• Canker

d f d d ll– made up of dead cells

• Girdling of conductive tissue

• More susceptible to 2° stress agents

• Death

Papery bark covering hyphal pegs

Anderson and Anderson, 1979

Papery bark covering hyphal pegs

Photo by USDA Forest Service Archive, bugwood.org

Predisposing Factorsp g

• Insect tunnels

• Wounds

• Open stand structureOpen stand structure

• Soil quality

• W • Water stress

• AgePhoto by Echo Thomsen

– 15-40 years old

• High humidity and low temperatures

Photo by William Livingston

Inciting Factorsg

• Canker girdles enough of the transport tissue to disrupt total tree Canker girdles enough of the transport tissue to disrupt total tree

functioning

Contributing factorsg

• Secondary fungal y g

infections

• WindAnderson and Anderson, 1979

Control Optionsp

• Do nothingDo nothing

• Harvest stand early if 15-25% infected

All b k– Allow aspen to grow back

• Harvest stand immediately if > 25% infection

– Grow a different species

• Conservative thinning

Anderson and Anderson, 1976

Photo by William Jacobi

Health Management Plan

for Quaking Aspen

• Preemptive Strategies– Grow quaking aspen on sites that it is adapted to

– Do not grow in open or fragmented stands

– Avoid thinning stressAvoid thinning stress

• Monitor and Survey– Monitor population patterns of FTC

– Egg counts

– Look for signs of fungal infection

• Reactive Strategiesg– Remove individuals infected with H. mammatum, possibly whole stands

– Leave genetically resistant clones whenever possible

P i id – Pesticides • B.T.

References

• Anderson, Ralph L. and Gerard W. Anderson. 1979. Hypoxylon Canker of Aspen. Forest Insect & Disease Leaflet 6, US Department of Agriculture Forest Service Washington D CDepartment of Agriculture Forest Service, Washington, D.C.

• Batzer, Harold O. and Robert C. Morris. 1978. Forest Tent Caterpillar. Forest Insect & Disease Leaflet 9, US Department of Agriculture Forest Service.

• Fergus, Charles. Trees of New England. Falcon Guide. Guilford. 2005. pp.14-22.

ld h ll ll h• Fitzgerald, Terrance D. The Tent Caterpillars. Cornell University Press. Ithaca. 1995.

• Little, E.L., Jr., 1971. Atlas of United States trees, volume 1, conifers and important hardwoods: U.S. Department of Agriculture Miscellaneous Publication 1146, 9 p., 200 maps.

• McDonough, Walter T. Sexual Reproduction, Seeds, and Seedlings.

• Meeker, James R. 2008. Forest Tent Caterpillar, Malacosoma disstria Hubner (Insecta: Lepidopter: Lasiocapidae) University of Florida IFAS Extension.

• Perala, D.A., Carpenter, E.M. 1985. Aspen: An American Wood. FS‐217. Washington, DC: U.S. Department of Agriculture, Forest Service. p 1‐4122

• Roland, Jens. 1993. Large-scale forest fragmentation increases the duration of tent caterpillar outbreak. Pecologia 93: 25-30.

• USDA Plants Profile http://www.fs.fed.us/wildflowers/communities/aspen/grow.shtml

Photo by godurando.com

QQuestions?

Photo by Anonymous